CWE-754 詳細

The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.

背景の詳細

導入モード

Implementation : The programmer may assume that certain events or conditions will never occur or do not need to be worried about, such as low memory conditions, lack of access to resources due to restrictive permissions, or misbehaving clients or components. Attackers may intentionally trigger these unusual conditions, thus violating the programmer's assumptions.
Implementation : REALIZATION: This weakness is caused during implementation of an architectural security tactic.

適用可能なプラットフォーム

言語

クラス： Not Language-Specific (Undetermined)
名前： Python (Undetermined)

テクノロジー

クラス： Not Technology-Specific (Undetermined)

一般的な結果

観察された例

潜在的な緩和策

Phases : Requirements
Phases : Implementation
Check the results of all functions that return a value and verify that the value is expected.
Phases : Implementation
If using exception handling, catch and throw specific exceptions instead of overly-general exceptions (CWE-396, CWE-397). Catch and handle exceptions as locally as possible so that exceptions do not propagate too far up the call stack (CWE-705). Avoid unchecked or uncaught exceptions where feasible (CWE-248).
Phases : Implementation
Phases : Implementation
Phases : Architecture and Design // Implementation
If the program must fail, ensure that it fails gracefully (fails closed). There may be a temptation to simply let the program fail poorly in cases such as low memory conditions, but an attacker may be able to assert control before the software has fully exited. Alternately, an uncontrolled failure could cause cascading problems with other downstream components; for example, the program could send a signal to a downstream process so the process immediately knows that a problem has occurred and has a better chance of recovery.
Phases : Architecture and Design
Use system limits, which should help to prevent resource exhaustion. However, the product should still handle low resource conditions since they may still occur.

検出方法

Automated Static Analysis

Automated static analysis may be useful for detecting unusual conditions involving system resources or common programming idioms, but not for violations of business rules.
有効性 : Moderate

Manual Dynamic Analysis

Identify error conditions that are not likely to occur during normal usage and trigger them. For example, run the program under low memory conditions, run with insufficient privileges or permissions, interrupt a transaction before it is completed, or disable connectivity to basic network services such as DNS. Monitor the software for any unexpected behavior. If you trigger an unhandled exception or similar error that was discovered and handled by the application's environment, it may still indicate unexpected conditions that were not handled by the application itself.

脆弱性マッピングノート

理由 : This CWE entry is a Class and might have Base-level children that would be more appropriate
コメント : Important: This entry is not exclusively about the use of exceptions and exception handling, which are just one type of mechanism for both checking and handling unusual or unexpected conditions. Examine children of this entry to see if there is a better fit.

ノート

Sometimes, when a return value can be used to indicate an error, an unchecked return value is a code-layer instance of a missing application-layer check for exceptional conditions. However, return values are not always needed to communicate exceptional conditions. For example, expiration of resources, values passed by reference, asynchronously modified data, sockets, etc. may indicate exceptional conditions without the use of a return value.

参考文献

REF-62

The Art of Software Security Assessment
Mark Dowd, John McDonald, Justin Schuh.

REF-62

The Art of Software Security Assessment
Mark Dowd, John McDonald, Justin Schuh.

REF-44

24 Deadly Sins of Software Security
Michael Howard, David LeBlanc, John Viega.

REF-622

Top 25 Series - Rank 15 - Improper Check for Unusual or Exceptional Conditions
Frank Kim.
https://www.sans.org/blog/top-25-series-rank-15-improper-check-for-unusual-or-exceptional-conditions/

REF-1541

Secure Coding Guide for Python
OpenSSF.
https://best.openssf.org/Secure-Coding-Guide-for-Python/

REF-1550

Secure PLC Coding Practices: Top 20 List
Secure PLC Programming project.
https://plc-security.com/

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